Well, we're all the protagonists of our own story. I'm sure some people think I'm a surly bastard.

My job can be pretty stressful too, but I rarely have to deal with a washroom stall covered in filth from the most disturbing case of explosive diarrhea ever.

Likewise I'm not usually expected to escort out a distraught, screaming homeless person who is having a psychotic episode in the middle of a busy convention center.

Hakuna Matata.

Just assume someone has dealt with something like that or worse and it gets easier to be nice to them, even when they're behaving like right old pricks.